CN110431900B - Method and apparatus for transmitting or receiving signal in wireless communication system - Google Patents

Abstract

A method for receiving downlink control information by a terminal in a wireless communication system according to one embodiment of the present invention comprises the steps of: receiving information on a reference subcarrier spacing (SCS) from among a plurality of SCS parameter sets; receiving downlink control information through a terminal group common Physical Downlink Control Channel (PDCCH); and acquiring information on the slot format from the downlink control information, wherein the downlink control information indicates the slot format based on the reference SCS, and the terminal may convert the slot format of the reference SCS according to the SCS of the terminal when the SCS of the terminal is different from the reference SCS.

Description

Method and apparatus for transmitting or receiving signal in wireless communication system

Technical Field

The present invention relates to a wireless communication system, and more particularly, to a method and apparatus for transmitting or receiving Downlink (DL) control information in a wireless communication system.

Background

First, an existing 3GPP LTE/LTE-A system will be briefly described. Referring to fig. 1, a ue performs initial cell search (S101). In the initial cell search procedure, the UE receives a primary synchronization channel (P-SCH) and a secondary synchronization channel (S-SCH) from the base station, performs downlink synchronization with the BS, and acquires information such as a cell ID. Thereafter, the UE acquires system information (e.g., MIB) through PBCH (physical broadcast channel). The UE can receive a DL RS (downlink reference signal) and check a downlink channel status.

After the initial cell search, the UE can acquire more detailed system information (e.g., SIB) by receiving a Physical Downlink Control Channel (PDCCH) and a physical downlink control channel (PDSCH) scheduled by the PDCCH (S102).

The UE may perform a random access procedure for uplink synchronization. The UE transmits a preamble (e.g., msg 1) through a Physical Random Access Channel (PRACH) (S103), and receives a response message (e.g., msg 2) of the preamble through a PDCCH and a PDSCH corresponding to the PDCCH. In case of contention-based random access, contention resolution procedures such as additional PRACH transmission (S105) and PDCCH/PDSCH reception (S106) may be performed.

Then, the UE can perform PDCCH/PDSCH reception (S107) and Physical Uplink Shared Channel (PUSCH)/Physical Uplink Control Channel (PUCCH) transmission (S108) as a general uplink/downlink signal transmission procedure. The UE can transmit UCI (uplink control information) to the BS. The UCI may include HARQ ACK/NACK (hybrid automatic repeat request acknowledgement/negative ACK), SR (scheduling request), CQI (channel quality indicator), PMI (precoding matrix indicator), and/or RI, etc.

Disclosure of Invention

Technical problem

An object of the present invention devised to solve the problem lies on a method and apparatus for more efficiently and accurately indicating a slot format through Downlink (DL) control information in a wireless communication system for supporting multiple subcarrier spacings (SCS).

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

Technical scheme

The object of the present invention can be achieved by providing a method of receiving Downlink (DL) control information by a User Equipment (UE) in a wireless communication system, the method comprising: receiving information on a reference subcarrier spacing (SCS) among a plurality of SCS parameter sets; receiving DL control information through a UE group common Physical Downlink Control Channel (PDCCH); and obtaining information on a slot format from the DL control information, wherein the DL control information indicates a slot format based on the reference SCS, and wherein the UE converts the slot format of the reference SCS according to the SCS of the UE when the SCS of the UE is different from the reference SCS.

In another aspect of the present invention, provided herein is a User Equipment (UE) for receiving Downlink (DL) control information, comprising: a receiver, and a processor configured to control the receiver to receive information on a reference sub-carrier spacing (SCS) among a plurality of SCS parameter sets, receive DL control information through a UE group common Physical Downlink Control Channel (PDCCH), and acquire information on a slot format from the DL control information, wherein the DL control information indicates the slot format based on the reference SCS, and wherein the processor converts the slot format of the reference SCS according to the SCS of the UE when the SCS of the UE is different from the reference SCS.

In another aspect of the present invention, provided herein is a method of transmitting Downlink (DL) control information by a Base Station (BS) in a wireless communication system, the method including: the method includes transmitting information on a reference subcarrier spacing (SCS) of a plurality of SCS parameter sets, generating DL control information including information on a slot format, and transmitting the DL control information to a UE group including the UE through a UE group common Physical Downlink Control Channel (PDCCH), wherein the BS informs the UE of the slot format based on the reference SCS even if the SCS of the UE is different from the reference SCS.

In another aspect of the present invention, there is provided a Base Station (BS) for performing the aforementioned DL control information transmission method.

The information on the reference SCS may be received via higher layer signaling.

The duration of the 1 slot may vary according to the SCS, and the reference SCS may be configured to be equal to or less than the SCS of the UE such that the duration of the 1 slot based on the reference SCS is equal to or greater than the duration of the 1 slot of the UE based SCS.

When the SCS of the UE is M times the reference SCS, the UE may interpret the 1 time slot based on the reference SCS as M consecutive time slots of the UE-based SCS.

The UE may determine whether each of a plurality of symbols included in a corresponding slot corresponds to a downlink (D), an uplink (U), or a flexible (X) based on the information on the slot format; and, wherein, when the SCS of the UE is M times the reference SCS, the UE may interpret one D, U, or X symbol based on the reference SCS as M D, U, or X symbols of the UE-based SCS.

The information on the slot format may indicate at least one of slot format combinations configured in the UE.

The UE may be configured with multiple frequency bands, and each slot format combination may be a combination of multiple slot formats in multiple frequency bands.

Each slot format combination is a combination of a slot format for a DL band and a slot format for an UL band. Alternatively, each slot format combination may be a combination of a slot format for a new radio access technology (NR) band and a slot format for a Long Term Evolution (LTE) band.

The slot format combinations configured in the UE may be received via higher layer signaling and may be a subset of a plurality of slot format combinations supported in the wireless communication system.

Advantageous effects

According to an embodiment of the present invention, a reference subcarrier spacing (SCS) is configured in a wireless communication system, wherein a plurality of SCS may be supported to accurately interpret a slot format, and the slot format may be commonly signaled to a UE group based on the reference SCS, and thus, a payload size of a Physical Downlink Control Channel (PDCCH) may be reduced and an overhead of the PDCCH may be reduced, compared to a case where the slot format is indicated for each individual SCS.

It will be appreciated by persons skilled in the art that the effects that can be achieved by the present invention are not limited to what has been particularly described hereinabove and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings.

Drawings

Fig. 1 illustrates a physical channel used in a 3GPP LTE/LTE-a system and a general signal transmission method using the physical channel.

Fig. 2 illustrates 1 slot based on subcarrier spacing (SCS) of 15kHz and 1 slot based on SCS of 60 kHz.

Fig. 3 illustrates a combination of slot formats according to an embodiment of the present invention.

Fig. 4 illustrates a combination of slot formats according to another embodiment of the present invention.

Fig. 5 and 6 illustrate a combination of slot formats according to another embodiment of the present invention.

Fig. 7 illustrates a combination of slot formats according to an embodiment of the present invention.

Fig. 8 illustrates a pattern of a slot format according to an embodiment of the present invention.

Fig. 9 illustrates reserved resource allocation for a group common Physical Downlink Control Channel (PDCCH) according to an embodiment of the present invention.

FIG. 10 illustrates a GSS deployed in a CSS, according to an embodiment of the present invention.

Fig. 11 illustrates GSS candidates having fixed positions in CSS according to an embodiment of the invention.

Fig. 12 and 13 illustrate slot patterns of a plurality of CCs according to an embodiment of the present invention.

Fig. 14 illustrates a slot pattern of a plurality of CCs according to another embodiment of the present invention.

Fig. 15 illustrates a flow of a method of transmitting and receiving Downlink Control Information (DCI) according to an embodiment of the present invention.

Fig. 16 illustrates a Base Station (BS) and a User Equipment (UE) according to an embodiment of the present invention.

Detailed Description

The following description of the embodiments of the present invention can be applied to various wireless access systems including CDMA (code division multiple access), FDMA (frequency division multiple access), TDMA (time division multiple access), OFDMA (orthogonal frequency division multiple access), SC-FDMA (single carrier frequency division multiple access), and the like. CDMA can be implemented with radio technologies such as UTRA (universal terrestrial radio access), CDMA 2000, etc. TDMA can be implemented with radio technologies such as GSM/GPRS/EDGE (global system for mobile communications)/general packet radio service/enhanced data rates for GSM evolution. OFDMA can be implemented with radio technologies such as IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, E-UTRA (evolved UTRA), etc. UTRA is part of UMTS (universal mobile telecommunications system). The 3GPP (third Generation partnership project) LTE (Long term evolution) is part of the E-UMTS (evolved UMTS) that uses the E-UTRA. The 3GPP LTE employs OFDMA in downlink and SC-FDMA in uplink. LTE-A (LTE-advanced) is an evolved version of 3GPP LTE.

For clarity, the following description mainly relates to a 3GPP LTE system or a 3GPP LTE-a system, to which the technical idea of the present invention may not be limited. Specific terms used in the following description are provided to help understanding of the present invention, and the use of terms can be modified into various forms within the scope of the technical idea of the present invention.

As many communication devices as possible have been required for as high a communication capacity as possible, and therefore, there has been a demand for enhanced mobile broadband (eMBB) communication as compared with a conventional Radio Access Technology (RAT) in the next-generation communication system discussed recently. In addition, large-scale machine type communication (mtc) for connecting a plurality of devices and objects to provide various services anytime and anywhere is also one of factors to be considered in next-generation communication. In addition, ultra-reliable and low latency communication (URLLC) has been discussed for next generation communication systems in view of reliability and latency sensitive services/User Equipment (UE).

Therefore, a new RAT considering eMBB, mtc, URLCC, etc. has been discussed for next generation wireless communication.

Some LTE/LTE-a operations and configurations that are not inconsistent with the design of the new RAT may also be applied to the new RAT. For convenience, the new RAT may be referred to as 5G mobile communication.

<NR frame structure and physical resource>

In the NR system, downlink (DL) and downlink (UL) transmissions may be performed through frames having a duration of 10ms, and each frame may include 10 subframes. Thus, 1 subframe may correspond to 1ms. Each frame may be divided into two half-frames.

The 1 subframe may include N _symb ^subframe,μ ＝N _symb ^slot ×N _slot ^subframe,μ A number of consecutive OFDM symbols. N is a radical of _symb ^slot Denotes the number of symbols per slot, μ denotes the OFDM parameter set, and N _slot ^subframe,μ Indicating the number of slots per subframe relative to the corresponding mu. In NR, a plurality of OFDM parameter sets shown in table 1 below may be supported.

[ Table 1]

μ	Δf＝2 μ ·15[kHz]	Cyclic prefix
			0	15	Is normal
1	30	Is normal
			2	60	Normal, extended
3	120	Is normal
			4	240	Is normal and normal

In table 1 above, Δ f refers to subcarrier spacing (SCS). The UE may be configured via UL signaling with μ and cyclic prefix for DL carrier bandwidth part (BWP) and μ and cyclic prefix for UL carrier BWP.

Table 2 below shows N of symbols with respect to each slot of the respective SCS in case of a normal CP _symb ^slot Number of symbols per frame, N _slot ^frame,μ And N of slots of each frame _slot ^subframe,μ The number of the cells.

[ Table 2]

Table 3 below shows the number N of symbols per slot with respect to each SCS in case of extended CP _symb ^slot Number of slots per frame N _slot ^frame,μ And the number of slots N per subframe _slot ^subframe,μ 。

[ Table 3]

Thus, in the NR system, the number of slots included in 1 subframe may vary according to subcarrier spacing (SCS). The OFDM symbol included in each slot may correspond to any one of D (DL), U (UL), and X (flexible). DL transmission may be performed in D or X symbols, and UL transmission may be performed in U or X symbols. The flexible resources (e.g., X symbols) may also be referred to as reserved resources, other resources, or unknown resources.

In NR, one Resource Block (RB) may correspond to 12 subcarriers in the frequency domain. The RB may include a plurality of OFDM symbols. The Resource Elements (REs) may correspond to 1 subcarrier and 1 OFDM symbol. Thus, there may be 12 REs on 1 OFDM symbol in 1 RB.

A carrier BWP may be defined as a set of contiguous Physical Resource Blocks (PRBs). Carrier BWP may also be referred to simply as BWP. A maximum of 4 BWPs may be configured for each UL/DL link in 1 UE. Even if multiple BWPs are configured, 1 BWP may be activated within a given time period. However, when a Supplemental Uplink (SUL) is configured in the UE, 4 BWPs may be additionally configured for the SUL, and 1 BWP may be activated for a given period of time. The UE may not expect to receive PDSCH, PDCCH, channel state information-reference signal (CSI-RS), or Tracking Reference Signal (TRS) in the activated DL BWP. In addition, the UE may not expect to receive PUSCH or PUCCH in the activated UL BWP.

<NR DL control channel>

In an NR system, a transmission unit of a control channel may be defined as a Resource Element Group (REG) and/or a Control Channel Element (CCE), etc.

The REGs may correspond to 1 OFDM symbol in the time domain and may correspond to 1 PRB in the frequency domain. In addition, 1 CCE may correspond to 6 REGs.

A brief description of the control resource set (CORESET) and Search Space (SS) will now be described. CORESET may be a set of resources used for control signal transmission, and the search space may be an aggregation of control channel candidates for performing blind detection. The search space may be configured for CORESET. For example, when one search space is defined on one CORESET, the CORESET for a Common Search Space (CSS) and the CORESET for a UE-specific search space (USS) may be separately configured. As another example, multiple search spaces may be defined in one CORESET. For example, CSS and USS may be configured for the same CORESET. In the following examples, CSS may refer to CORESET with CSS configured therefor, and USS may refer to CORESET with USS configured therefor, and so on.

The base station may signal information about CORESET to the UE. For example, the CORESET configuration for each CORESET and the duration of the corresponding CORESET (e.g., 1/2/3 symbol) may be signaled. When interleaving is applied for distributing CCEs to 1 symbol CORESET, 2 or 6 REGs may be bundled. Bundling of 2 or 6 REGs may be performed on a 2 symbol CORESET and a time-first mapping may be applied. Bundling of 3 or 6 REGs may be performed for 3 symbol CORESET and time-first mapping may be applied. When performing REG bundling, the UE may assume the same precoding for the corresponding bundling units.

<Time slot format indication>

A slot type and an operation method of the UE when the Guard Period (GP) is maintained or changed will now be described. In addition, a method of processing a slot type indication and a method of indicating reserved resources when changing a parameter set of a slot type are described below. The slot type may be referred to as a slot format.

1. Timeslot type indication

The UE may receive information about the slot type. The information on the slot type may indicate the slot type, and may include information on, for example, a downlink pilot time slot (DwPTS), an uplink pilot time slot (UpPTS), a Guard Period (GP), and reserved resources.

The information on the slot type may be transmitted periodically or aperiodically. Whether to apply the received slot type indication information may be determined by the UE or may be mandatory.

For example, information on the slot type may be received through the PDCCH. For example, information on the slot type may be received through a common PDCCH, or may also be received through UE-specific control information (e.g., DCI).

The information on the slot type received through the common PDCCH may be control information for indicating the slot type in common to a specific UE group or all UEs in a cell. The information on the slot type received through the UE-specific PDCCH may be control information indicating the slot type of each UE.

2. Guard Period (GP)

(1) Time slot based GP, all of which are configured in DL or UL

The GP may be defined according to the end position of the DwPTS and the start position of the UpPTS.

The GP may be located subsequent to the DwPTS. The end position of the DwPTS may be transmitted to the UE through the common PDCCH. For example, the UE may calculate the GP based on the end position of the transmitted DwPTS, the UpPTS, and the UL slot in which transmission is to be performed. Separately, an indication of the GP may be signaled to the UE.

The GP may be positioned before the UpPTS. The UE may receive information on the start position of the UpPTS through the common PDCCH. The UE may use the start position of the UpPTS as the end position of the GP without change, or the UE may determine the end position of the GP based on the start position of the UpPTS.

The GP may exist only in the slots or may exist between the slots. The position and length of the GP may be unlimited. When DL slots and UL slots exist consecutively, GP may exist between slots. For example, GP may exist between DL and UL slots.

A method of forming a GP per UE or per UE group may be configured. The configuration of the GP may be cell common or may be predefined.

Each UE or UE group may be configured with a GP, and in this case, more or less cell-specific GPs may be configured than signaled to each UE or UE group. For example, when the number of GPs of the UE is less than the cell-specific GPs or the common GPs of the group, the additional resource may be used as the GPs according to the dynamic indication, and when the number of GPs of the UE is greater than the cell-specific GPs or the common GPs of the group, the additional GPs may be formed according to a predetermined rule.

(i) When GP remains constant

After the GP is configured once, the GP of the UE may remain constant and may not be affected by the common PDCCH. For example, a cell-common or group-common GP transmitted in a System Information Block (SIB) or the like may not be changed by the common PDCCH. In addition, the indication of GP in the common PDCCH may be omitted.

For example, when the GP is a 5-symbol and one slot is a 14-symbol, D, U, or reservation with respect to 9 symbols may be indicated. In addition, the GP may be configured for each subframe or for each slot set. The GP configuration may be given as a fallback configuration. For example, a GP configured in fallback may always be assumed for the common PDCCH. A fixed DL, UL, GP or reservation configured in the fallback may be assumed and, therefore, a corresponding indication may be omitted from the common PDCCH.

(ii) When GP can be changed by common PDCCH

The GP of the UE may be changed through the common PDCCH. There may be no problem when the UE normally receives the common PDCCH, but there may be a problem in GP configuration when the common PDCCH cannot be received.

Therefore, the network needs to inform the UE of the minimum GP and the maximum GP supported by the cell. The minimum GP may be defined not to be changed by the common PDCCH. For example, the minimum GP may be 0.

a. Fallback operation when common PDCCH is lost

Upon determining that the UE did not receive or send a slot type indication, the UE may maintain the most recently indicated slot type.

In addition, when a specific slot type is preconfigured to the UE via semi-static signaling and the UE loses the slot type indication or cannot receive the slot type indication, the slot type preconfigured via semi-static signaling may be used.

A best/worst case GP for backoff may be defined. When the common PDCCH is defined to indicate the best GP, signaling the GP for backoff may also be configured as the best GP. When the common PDCCH is defined to indicate the worst GP, the GP signaled for backoff may also be configured as the worst GP.

The GP of the best/worst case GP applied for backoff may be predefined or may be configured by the network. This may be required to define the operation of the UE when applying the fallback configuration.

(2) When all UEs in a cell use the same GP

An environment in which all UEs in a cell use the same GP may be considered. The size of the DwPTS in which the UE receives a signal and the size of the UpPTS in which the UE transmits a signal may be the same for all UEs or may be different for the UEs.

When the DwPTS/UpPTS size is different for each UE, the PTS of each UE may be configured to be sufficiently placed in the slot type indicated by the PTS. For example, even if the size of DwPTS/UpPTS is different for each UE, the size of DwPTS/UpPTS of all UEs may be the size of PTS in which UL/DL transmission and reception is enabled without a change in the slot type indicated in common by the UE group. Alternatively, in practice, the DwPTS/UpPTS sizes of all UEs may be the same.

(3) When different for each UEGP

An environment in which all UEs in a cell can use different GPs may be considered. The size of DwPTS of UE reception signal and the size of UpPTS of UE transmission signal may be the same for all UEs or may be different for each UE.

When the UEs are notified about the GP information through the common PDCCH, the network may configure the end positions of the DwPTS of all the UEs to be the same. For example, the end position of the DwPTS may be the closest point, the earliest point, or the middle point among the end points of the DwPTS of the UE in the cell.

(i) When the nearest end point of DwPTS is indicated

The end position of the DwPTS indicated by the network may be the closest point among the end points of the DwPTS of the UE in the cell. Accordingly, the end position of the DwPTS of the specific UE may be earlier than the end position of the DwPTS indicated through the common PDCCH. In this case, the UE may first terminate DL reception, and thus may further transmit UL data within a guaranteed time period, or may transmit UL data only in UpPTS.

(ii) When the earliest end point of DwPTS is indicated

The end position of the DwPTS indicated by the network may be the earliest of the end points of the DwPTS of the UE in the cell. Accordingly, the end position of the DwPTS of the specific UE may be later than the end position of the DwPTS indicated by the common PDCCH. In this case, when the start position of the UpPTS of the UE is within the GP, the corresponding UE may transmit the UpPTS in the UL without change, and when the start position of the UpPTS is not within the GP, the UE may shorten the UpPTS and transmit the UpPTS in the UL or may skip UL transmission on the corresponding UpPTS.

(iii) When indicating the end position of the average DwPTS

The end position of the DwPTS indicated by the network may be an average point among the end points of the DwPTS of the UE in the cell. Accordingly, the end position of the DwPTS of a specific UE may be later or earlier than the end position of the DwPTS indicated by the common PDCCH. In consideration of this, two UpPTS types may be defined as a short UpPTS and a long UpPTS, and the UE may prepare transmission for the two UpPTS types.

3. Handling of different parameter sets and slot sizes

The slot size may also be changed when changing the parameter set of DwPTS, upPTS, etc. transmitted and received by the UE. The operation of the UE and the used time slot may be changed based on the parameter set indication currently used by the UE or based on the reference parameter set indication according to the type of time slot indicated by the common PDCCH.

For example, a reference parameter set as a reference for indicating a slot type may be defined/configured. When the slot type is indicated based on the reference parameter set, the UE may change and interpret the indicated slot type according to the parameter set used by the UE. The UE may change a slot size indicated by the reference parameter set based on the common PDCCH to a slot size corresponding to a parameter set used by the UE, and may apply the changed slot size.

As another example, when the network indicates the slot type, the network may indicate the slot type according to a set of parameters used by the UE. In this case, the UE may apply the slot type indicated by the network without change, instead of separately calculating the slot size.

4. Periodic resource allocation

Among the resources required to maintain the connection of the UE with the network, there may be undefined resources or undefined slot types. To use such resources, the network may signal the configuration of the corresponding resource using a common PDCCH, or may basically define a static configuration regarding the use of the corresponding resource.

(1)CSI-RS

In order to receive the CSI-RS by the UE, the following method may be considered.

(i) For example, a UE may be defined to always receive periodic CSI-RS. Without a separate indication for CSI-RS reception, the UE may assume that the periodic CSI-RS is always transmitted by the network and may operate.

(ii) As another example, the UE may know in advance candidate resources in which the periodic CSI-RS is to be transmitted, and the network may inform the UE whether the CSI-RS is actually transmitted to the corresponding resources through the common PDCCH. In this case, the load may be reduced compared to a case where the UE always receives the CSI-RS, but the UE needs to properly receive the common PDCCH to receive the CSI-RS.

The network may also configure methods (i) and (ii) according to channel conditions.

For example, CSI-RS may be classified into two types. The network may distinguish between guaranteed CSI-RS where transmission is guaranteed and potential CSI-RS where transmission will be enabled, and may send CSI-RS configurations. The CSI-RS is guaranteed to be transmitted always without indication through the common PDCCH, and transmission of potential CSI-RS can be activated through the common PDCCH or other control signals.

Guaranteed CSI-RS can be used for periodic CSI reporting and potential CSI-RS can also be used for aperiodic CSI reporting, triggered when necessary.

Both the guaranteed CSI-RS and the potential CSI-RS may be used for periodic/aperiodic CSI measurements.

Alternatively, the UE may selectively use two types of CSI-RS according to the situation.

(2) License exempt resource

In NR, a grant-less resource may be configured in which a UE performs UL transmission without receiving DCI corresponding to a UL grant.

For example, there may be: always an unlicensed resource, which is always used as an unlicensed resource; and a flexible unlicensed resource configured as an unlicensed resource according to a dynamic indication through the common PDCCH.

The UE may use the always unlicensed resources even if the UE does not receive an indication of flexible resources.

For example, always unlicensed resources may facilitate flexible unlicensed resources.

In a state where the UE knows all candidates of the unlicensed resources in advance, the network may indicate the unlicensed resources to be used by the corresponding UE through the common PDCCH. In this case, when the common PDCCH is properly received, there may be a limitation in that the UE can use the unlicensed resource but the unlicensed resource in the system may be minimized.

The network may determine a UE group that can attempt to access each of the unlicensed resources and may also notify only the corresponding group of the unlicensed resources through a common PDCCH. In this case, the common PDCCH may include identification information on UEs that can access the corresponding unlicensed resources.

The UEs that can access the corresponding unlicensed resources may be determined according to the priorities. For example, the priority may be determined based on a failure rate of the number of access attempts, or may be determined based on a size/urgency of UL data to be transmitted.

This method of configuring the always (or fixed)/flexible resources may also be applied to semi-static resources such as radio resource management reference signal (RRM-RS) resources, random Access Channel (RACH) resources, and Synchronization Signal (SS) block resources.

More specifically, in case of RRM-RS, fixed resources may be used for neighbor cell measurement and flexible resources may be used for serving cell measurement. Transmission/reception points (TRPs) may exchange configurations of fixed resources with each other and may configure the exchanged configurations for the UE.

The fixed resources may be configured with a longer period of time than the flexible resources, and the period of time of the fixed resources may affect the latency/accuracy of the neighbor cell measurements. For a neighboring cell with an excellent measurement result equal to or greater than a threshold, the UE may be configured to perform measurements on flexible resources of the neighboring cell. To perform measurements in flexible resources of the neighbor cell, the UE may read the common PDCCH of the neighbor cell. For example, the serving cell may signal information about the configuration of the common PDCCH of the neighbor cells and information about a transmission method such as a period to the UE, and the neighbor cells may broadcast the corresponding information through SIBs or the like.

In addition, neighbor cell measurement reporting for UEs using flexible resources may be triggered by the network. For example, the flexible resources may be additionally used only in the aperiodic RRM report triggered by the network.

<Overview of slot type indication and additional proposals>

Other proposals than the above are described below.

To design a group common PDCCH for slot type indication, the potential difference in NR compared to the enhancements of LTE TDD for DL-UL interference management and traffic adaptation (LTE eIMTA) needs to be considered. For example, it may need to be considered to configure different GP lengths for the respective UEs in the NR. This consideration may be even more important when different UEs use different sets of parameters or are associated with different usage scenarios. In addition, an indication of the slot structure in an NR network providing multiple parameter sets may need to be considered.

The relationship between the semi-static configuration and the dynamic slot type indication may also need to be considered and, for example, the dynamic indication may overwrite the semi-static configuration for measurements for more flexible NR system design than LTE.

UE-specific GP configuration

In unpaired spectrum, where UL and DL are used in TDM fashion, it can generally be assumed that the network operates once in either UL and DL, regardless of the set of parameters used.

In the LTE system, a cell-specific GP length may be configured for all UEs. However, it may be inefficient to configure the same GP length for all UEs in a cell in an NR system. For example, when the GP length is configured to be 2 symbols based on the parameter set corresponding to the SCS of 15kHz, the corresponding GP length may correspond to 8 symbols in the parameter set corresponding to the SCS of 60 kHz. As such, the GP length corresponding to 8 symbols may be a longer period of time than what is actually required for a UE operating based on 60kHz SCS, and radio resources may be wasted.

The UE-specific GP configuration may be more appropriate than the cell-specific/UE-common GP configuration in the NR, considering different propagation delays, different parameter sets and/or different QoS requirements. To use the UE-specific GP, the maximum GP supported by the network may be signaled to the UE. In addition, a UE-specific GP may be determined and signaled.

In this way, NR may support UE-specific GP configuration.

2. UE operation according to slot type

When a slot type indication is given, the UE may determine DL symbols, UL symbols, and/or other symbols (e.g., flexible symbols) from the slot type indication. Details regarding the timeslot type indication may indicate, for example, one of a predefined timeslot mode, a bitmap of DL/UL, and/or lengths of DwPTS and UpPTS, but is not limited thereto. To indicate the correct slot type, a process of defining different GP lengths may be required.

In signaling for the DL part (resource) and the UL part (resource) of the group-common PDCCH, two methods can be broadly considered.

(i) The first method is to indicate the basic case of the DL/UL part through the network. For example, the DL/UL portion may be indicated according to the minimum GP supported by the network. In this case, a UE having a GP length greater than the minimum GP may determine the location of additional required GPs based on the indicated slot structure.

(ii) The second method is to indicate the worst case of the DL/UL part by the network. For example, the DL/UL portion may be indicated according to the maximum GP supported by the network. In this case, a separate mechanism for using other resources (e.g., flexible) indicated by the slot indication may be used for DL or UL of UEs having a GP smaller than the maximum GP.

In addition, it may be necessary to determine a location where a GP indicated by a slot type is located with respect to UEs having different GP lengths.

For example, the UE may assume that the GP is always ended after the DL portion. When slot 1 is dedicated to DL and slot 2, which is positioned after slot 1, is dedicated to UL, GP may be positioned at the beginning of slot 2, which is dedicated to UL. When the minimum GP is indicated according to the slot type indication, UEs having a GP larger than the minimum GP may reduce the UL part to ensure additional GPs.

As another example, the UE may assume that the GP is always positioned before the start of the UL portion. When slot 1 is dedicated to DL and slot 2 is dedicated to UL, GP can be positioned in DL slot. When the minimum GP is indicated by the slot type indication, UEs having a GP larger than the minimum GP may reduce the DL portion to ensure additional GPs.

Alternatively, the GP may be generated only by dynamic scheduling. For example, the UE may create a GP between the end of DL reception (e.g., the end of control channel, the end of DL data, or the end of measurements) and the start of UL transmission. However, this approach may complicate the operation of the UE. Therefore, it may be preferable to determine whether to insert the GP into the end of the DL or the beginning of the UL.

Based on the above discussion, it may be desirable to determine whether the best GP situation or the worst GP situation assumed to be supported by the network forms the slot structure indicated by the common PDCCH. In addition, the GP may be positioned after the DL portion or before the UL portion.

3. Handling of different parameter sets and different slot sizes

The slot size may be related to the parameter set. When changing the parameter set of DL or UL, the actual effect may be changed according to the relationship between the parameter set used in the slot type indication and the parameter set used in the control/data transmission. The common PDCCH may indicate a slot type, and a parameter set used as a reference for the slot type indication may be important for the UE.

For example, the slot type indication may be sent based on a reference parameter set. Based on the reference parameter set, the UE may interpret the indicated slot type as a parameter set for the UE, and may estimate an appropriate size of the slot, regardless of the parameter set used in the UE.

As another example, the common PDCCH may indicate the slot type using a set of parameters for the UE. In this case, the UE may not need to re-estimate the slot type and slot size. In this case, the UE may need to separately transmit the common PDCCH according to the parameter set.

However, as described above, the network may operate in one direction (e.g., DL/UL) at a time, regardless of the set of parameters used. Therefore, it may be advantageous to send a slot type indication based on a reference parameter set. For example, when the network operates based on a set of parameters for 15kHz and 60kHz SCS and sends a slot type indication based on 15kHz SCS, a UE using 60kHz SCS may interpret different numbers of DL portions (e.g., DL symbols) and UL portions (e.g., UL symbols) as indicated based on symbol-level alignment or slot-level alignment.

As a detailed example, fig. 2 illustrates 1 slot of SCS based on 15kHz and 1 slot of SCS based on 60 kHz. That is, 1 symbol duration (i.e., time duration segment) of 15 kHz-based SCS may be the same as 4 symbol durations of 60 kHz-based SCS. Assuming that a slot format indication based on 15kHz SCS indicates a slot format with [ symbol 0= DL, symbol 2= DL., symbol 13= UL ], a UE operating based on 60kHz SCS may interpret symbol 0= DL as 4 consecutive DL symbols, may interpret symbol 2= DL as 4 consecutive DL symbols, and may interpret symbol 13= UL as 4 consecutive UL symbols (e.g., symbol-level alignment). Slots having the indicated format may be interpreted as being repeated four times, depending on the slot level alignment.

Such SCS of 15kHz and 60kHz is exemplary, and the same method can be applied to the various SCS already mentioned with reference to table 1 above. For example, when SCS 1 is a kHz, SCS 2 is B kHz, and the relationship of B = a × M (where a, B, and M are natural numbers) is satisfied, the length of 1 OFDM symbol based on SCS 1 may be the same as the length of M OFDM symbols based on SCS 2.

The group common PDCCH may indicate the slot format based on the reference parameter set, regardless of the actual parameter set used in the UE.

The set of reference parameters may be indicated or pre-configured by the network (e.g., RRC signaling). For example, the smallest SCS of the various SCS's configured by the network for the UE may be used as the reference parameter set.

4. UE operation related to periodic resource configuration

In general, NR may be targeted to avoid constant signaling or periodic transmission, and certain operations may require certain periodic configurations. For example, a Synchronization Signal (SS) block, a PRACH configuration, a CSI-RS configuration, a RRM-RS configuration, and/or an unlicensed resource may be configured periodically.

In terms of UE performance, it may be desirable to ensure semi-statically configured resources. However, dynamic resource switching between DL/UL/reservations may be limited in terms of flexibility. In view of these advantages and disadvantages, the following two methods can be considered.

(i) For example, when providing a semi-static configuration, the UE may assume that resources are used according to the corresponding configuration. For example, a group common PDCCH may be defined to not change the type of resources configured by the semi-static configuration. This approach may be beneficial to enhance UE performance and simplify fallback operation.

(ii) As another example, the resources indicated by the semi-static configuration may be considered potential candidates for semi-static resources. When the group common PDCCH is not activated, it may be assumed that potential candidates are guaranteed. When the group common PDCCH is activated, the semi-static resource may be used only when checked by the group common PDCCH. According to this approach, it may be advantageous to enhance network flexibility. However, even if the slot type is not changed in the semi-statically configured fallback configuration, the group common PDCCH may need to be transmitted, and thus signaling overhead may be increased.

In view of the advantages/disadvantages of (i) and (ii), the semi-static resource may distinguish between a first group and a second group, the first group may conform to operation (i), and the second group may conform to operation (ii). Minimum UE performance and minimum chance of PRACH that can be guaranteed to be measured by the first and second groups can be used in an on-demand manner.

The common PDCCH may cover at least a portion of the semi-statically configured resources. Semi-static configurations having a different priority than the common PDCCH may be considered, e.g., guaranteed resources and flexible resources.

<Time Slot Format Indicators (SFI) for different parameter sets>

As described above, the slot format indicated by the group common PDCCH may include downlink (D), unknown (X), and/or uplink (U) symbols.

The multiple slot formats may be configured in various combinations, and the combinations of slot formats may be configured for the UE via higher layer signaling or the like.

Multiple parameter sets may be configured for a UE. The SFI of the group common PDCCH may indicate an index of a configured or UE's slot format table (or slot format combination/set). When multiple BWPs and multiple parameter sets are configured for 1 UE, there may be a method of indicating a slot format of each parameter set. For example, the parameter set may be separately configured for each BWP, and in this case, the slot format may be indicated for each BWP.

1.UE slot format table for multiple parameter sets

(1) List of documents

The slot format table configured for the UE may be a slot format set of a plurality of parameter sets.

For example, when the SCS configured for the UE is 15 and 30kHz and the slot format table configured for the UE includes 16 total entries, entries #1 to #8 may correspond to the slot format of the SCS of 15kHz and entries #9 to #16 may correspond to the slot format of the SCS of 30kHz. The SFI of the group common PDCCH may indicate a slot format index suitable for a parameter set used by the UE.

When a plurality of BWPs are activated in the UE and each BWP has a different number, the slot formats of the plurality of BWPs may be indicated by one SFI. For example, an index offset between slot formats to be applied to parameter sets may be used to indicate slot formats of a plurality of BWPs by 1 SFI.

Similar to the above example, it may be assumed that when the SCS configured for the UE is 15 and 30kHz and the slot format table configured for the UE includes 16 total entries, the entries #1 to #8 correspond to the slot format of the SCS of 15kHz, and the entries #9 to #16 correspond to the slot format of the SCS of 30kHz. In this case, when the SFI indicates one index of #1 to #8, the UE may acquire the slot format without change using the index of the SFI in the BWP of the SCS of 15kHz, but may interpret the index of SFI +8 in the BWP of the SCS of 30kHz (i.e., apply the index offset of 8) to acquire the slot format of the BWP of the SCS of 30kHz.

(2) Multi-list

The parent table, which is a reference to the slot format table configured for the UE, or the slot format table configured for the UE may correspond to a set of slot formats of a plurality of parameter sets.

For example, as shown in table 4, a column may be defined for each parameter set, and the column may define a slot format suitable for the corresponding parameter set.

[ Table 4]

	15kHz SCS	30kHz SCS	60kHz SCS	120kHz SCS	…
						Time slot format 1	…	…	…	…	…
Time slot format 2	…	…	…	…	…
						…
Time slot format N	…	…	…	…	…

When a plurality of BWPs are activated in the UE and each BWP has a different parameter set, the UE can recognize the slot format of each parameter set in the row corresponding to the SFI even if one SFI is indicated.

2. Automatic slot format expansion/contraction

As another example of the present invention, a UE slot format table of one parameter set (e.g., a reference parameter set) may be defined, and a rule may be defined to expand or contract the corresponding table according to the parameter set. In this case, it may not be necessary to separately indicate the slot format by the network parameter set, and thus signaling overhead may be advantageously reduced.

(1) Extending rules

When the UE uses a larger SCS than the reference SCS as a reference for the UE slot format table, the number of UE SCS based slots may be increased compared to the number of reference SCS based slots included in the same duration. For example, 4 slots of a reference SCS based on 15kHz may have the same duration as 8 slots of an SCS based on 30kHz. Therefore, the UE needs to extend the slot format based on the reference SCS indication according to the SCS used by the UE. Here, the extension of the slot format refers to the extension of the number of symbols included in a slot, not the extension of the absolute duration. For example, when the network indicates a time direction of 0.5ms including 14 symbols, the UE may be interpreted to extend to include 28/56/... Eta.symbols within the same duration of 0.5 ms.

-option 1: the downlink (D), unknown (X) and uplink (U) directions of the symbols of the respective slot formats indicated by the reference SCS may be maintained for the duration occupied by the respective slot format. For example, it may be assumed that the reference SCS is 15kHz and the slot format indicated by the reference SCS includes 4D symbols, 6X symbols, and 4U symbols, and the SCS used by the UE is 30kHz. In this case, for a UE operating based on 30kHz SCS, 4D symbols, 6X symbols, and 4U symbols included in the indicated slot format may be extended to 8D symbols, 12X symbols, and 8U symbols, respectively. That is, the duration of 4D symbols based on the SCS of 15kHz is the same as the duration of 8D symbols based on the SCS of 30kHz, and thus, the UE may interpret the 4D symbols indicated by the SCS of 15kHz as 8D symbols based on the SCS of 30kHz. In this case, the number of D symbols may be extended, but the sum of the durations of the D symbols in the slot may be maintained. The UE can interpret the X symbol and the U symbol in the same manner.

-option 2-1: when the UE extends each D symbol and each U symbol, different rules may be applied according to whether there is an X symbol before and after the corresponding symbol. For example, when the D symbol whose rear is the X symbol is extended to a case where the SCS used by the UE is equal to or greater than twice the reference SCS, the UE may configure 1/2 of the rear of the extended D symbol as X. When a U symbol whose front is an X symbol is extended, the UE may configure 1/2 of the front of the extended U symbol as X. For example, when the reference SCS is 15kHz and the numbers of D symbols, X symbols, and U symbols are 4, 6, and 4, respectively, the 4D symbols may be extended to 4D symbols + 4X symbols based on the SCS of 30kHz. The 6 indicated X symbols may be extended to 12X symbols. Based on the 30kHz SCS, the 4 indicated U-symbols can be extended to 4X-symbols + 4U-symbols. As a result, the slot format may be interpreted as 4D symbols + 20X symbols + 4U symbols. Therefore, the duration corresponding to the X symbol can be further increased compared to the indicated slot format.

-option 2-2: when the SCS used by the UE is equal to or greater than 4 times the reference SCS and the D symbol whose rear part is the X symbol is spread, the UE may configure the rear 1/4 of the spread D symbol as the X symbol. When a U symbol whose front is an X symbol is extended, 1/4 of the front of the extended U symbol may be configured as an X symbol.

-option 2-3: when the SCS used by the UE is equal to or greater than 8 times the reference SCS and the D symbol whose rear part is the X symbol is spread, the UE may configure 1/8 of the rear part of the spread D symbol as the X symbol. When a U symbol whose front is an X symbol is extended, 1/8 th of the front of the extended U symbol may be configured as an X symbol.

-options 2-4: when the SCS used by the UE is equal to or greater than 16 times the reference SCS and the D symbol whose rear part is the X symbol is spread, the UE may configure the rear 1/16 of the spread D symbol as the X symbol. When a U symbol whose front is an X symbol is extended, 1/16 of the front of the extended U symbol may be configured as an X symbol.

-option 3-1: when the SCS used by the UE is equal to or greater than twice the reference SCS and the X symbol is spread, the format of the spread X symbol may also be differently determined according to whether the D/U symbol occurs before and after the X symbol. For example, when an X symbol whose front is a D symbol is extended, the UE may configure 1/2 of the front of the extended X symbol as a D symbol. In addition, when an X symbol whose rear is a U symbol is extended, the UE may configure 1/2 of the rear of the extended X symbol as a U symbol.

-option 3-2: when the SCS used by the UE is equal to or greater than 4 times the reference SCS and extends the X symbols, the format of the extended X symbols may be differently determined according to whether the D/U symbols occur before and after the X symbols. For example, when an X symbol whose front is a D symbol is extended, the UE may configure 1/4 of the front of the extended X symbol as a U symbol. In addition, when an X symbol whose rear is a U symbol is extended, the UE may configure 1/4 of the rear of the extended X symbol as a U symbol.

-options 3-3: when the SCS used by the UE is equal to or greater than 8 times the reference SCS and extends the X symbols, the format of the extended X symbols may also be differently determined according to whether the D/U symbols occur before and after the X symbols. For example, when an X symbol whose front is a D symbol is extended, the UE may configure 1/8 of the front of the extended X symbol as a U symbol. In addition, when an X symbol whose rear is a U symbol is extended, the UE may configure 1/8 of the rear of the extended X symbol as a U symbol.

-options 3-4: when the SCS used by the UE is equal to or greater than 16 times the reference SCS and extends the X symbols, the format of the extended X symbols may also be differently determined according to whether the D/U symbols occur before and after the X symbols. For example, when an X symbol whose front is a D symbol is extended, the UE may configure 1/16 of the front of the extended X symbol as a U symbol. In addition, when an X symbol whose rear is a U symbol is extended, the UE may configure 1/16 th of the rear of the extended X symbol as a U symbol.

(2) Narrowing rules

When the UE uses a smaller SCS than the reference SCS, there may be a smaller number of slots/symbols in the same duration than indicated based on the reference SCS. For example, 8 slots of a reference SCS based on 30kHz may have the same duration as 4 slots of an SCS based on 15 kHz. Therefore, the UE needs to extend the slot format based on the reference SCS indication according to the SCS used by the UE.

-option 1-1: when the SCS used by the UE (hereinafter, UE SCS) is smaller than the reference SCS and even one of D or U exists in the symbol set of the reference SCS to be reduced to 1 symbol of the UE SCS, the corresponding symbol set may be interpreted as one D symbol or U symbol based on the UE SCS.

-options 1-2: when the UE SCS is small and equal to or less than 1/2 times the reference SCS and the portion of D or U in the symbol set of the reference SCS to be reduced to 1 UE SCS symbol is equal to or greater than 1/2, the corresponding symbol set may be configured as D or U symbol of the UE SCS. When the fraction of D or U is less than 1/2, the corresponding symbol set may be configured as X symbols of the UE SCS. For example, when indicating a slot format dddxxxxxxxuuuu based on a reference SCS of 30kHz, 2 symbols such as | DD | DX | XX | XU | UU | may be grouped to define 1 symbol of UE SCS of 15 kHz. | DX | can be converted to D and | XU | can be converted to U. The slot format dddxxxxxuuuu of the SCS based on 30kHz may be converted into the slot format DDXXXUU of the UE SCS based on 15 kHz.

-options 1-3: when the UE SCS is small and equal to or less than 1/4 times the reference SCS and the portion of D or U in the symbol set of the reference SCS to be reduced to 1 UE SCS symbol is equal to or greater than 3/4, the corresponding symbol set may be configured as D or U symbol of the UE SCS. When the fraction of D or U is less than 3/4, the corresponding symbol set may be configured as X symbols of the UE SCS.

-options 1-4: when the UE SCS is small and equal to or less than 1/8 times the reference SCS and the portion of D or U in the symbol set of the reference SCS to be reduced to 1 UE SCS symbol is equal to or greater than 7/8, the corresponding symbol set may be configured as D or U symbol of the UE SCS. When the fraction of D or U is less than 7/8, the corresponding symbol set may be configured as X symbols of the UE SCS.

-options 1-5: when the UE SCS is small and equal to or less than 1/16 of the reference SCS and the portion of D or U in the symbol set of the reference SCS to be reduced to 1 UE SCS symbol is equal to or greater than 15/16, the corresponding symbol set may be configured as D or U symbol of the UE SCS. When the fraction of D or U is smaller than 15/16, the corresponding symbol set may be configured as X symbols of the UE SCS.

-option 2-1: when the UE SCS is smaller than the reference SCS and even one X exists in the symbol set of the reference SCS to be reduced to 1 symbol of the UE SCS, the corresponding symbol set may be converted into X symbols of the UE SCS.

-option 2-2: when the UE SCS is small and equal to or less than 1/2 times the reference SCS, the symbol set of the reference SCS to be reduced to 1 symbol of the UE SCS includes D and X or X and U, and a portion of X in the symbol set is equal to or greater than 1/2, the corresponding symbol set may be configured as X symbols of the UE SCS. When the fraction of X in a symbol set is less than 1/2, the corresponding symbol set may be configured as D or U symbols of the UE SCS.

-option 2-3: when the UE SCS is small and equal to or less than 1/4 times the reference SCS, the symbol set of the reference SCS to be reduced to 1 symbol of the UE SCS includes D and X or X and U, and a portion of X in the symbol set is equal to or greater than 3/4, the corresponding symbol set may be configured as X symbols of the UE SCS. When the X part in a symbol set is less than 3/4, the corresponding symbol set may be configured as D or U symbol of the UE SCS.

-options 2-4: when the UE SCS is small and equal to or less than 1/8 times the reference SCS, the symbol set of the reference SCS to be reduced to 1 symbol of the UE SCS includes D and X or X and U, and a portion of X in the symbol set is equal to or greater than 7/8, the corresponding symbol set may be configured as X symbols of the UE SCS. When the fraction of X in a symbol set is less than 7/8, the corresponding symbol set may be configured as D or U symbols of the UE SCS.

-options 2-5: when the UE SCS is small and equal to or less than 1/16 times the reference SCS, the symbol set of the reference SCS to be reduced to 1 symbol of the UE SCS includes D and X or X and U, and a portion of X in the symbol set is equal to or greater than 15/16, the corresponding symbol set may be configured as X symbols of the UE SCS. When the fraction of X in a symbol set is less than 15/16, the corresponding symbol set may be configured as D or U symbols of the UE SCS.

-option 3: when the UE SCS is smaller than the reference SCS and the symbol set of the reference SCS to be reduced to 1 SCS symbol includes all of D, X, and U, the corresponding symbol set may be configured to be the X symbol of the UE SCS.

-option 4-1: when the UE SCS is smaller than the reference SCS and D and U are mixed in the symbol set of the reference SCS to be reduced to 1 SCS symbol, the corresponding symbol set may be configured as X symbols of the UE SCS.

-option 4-2: when the UE SCS is smaller than the reference SCS and D and U are mixed in the symbol set of the reference SCS to be reduced to 1 SCS symbol, the UE may recognize the corresponding symbol set as an error and may ignore the slot format of the slot included in the corresponding symbol set.

(3) Default of reference parameter set

There may be various methods of informing the UE about the reference parameter set to configure the reference parameter set through the network.

-option 1: for example, when the UE is notified of the slot format table (e.g., a combination of slot formats), the network may also notify the UE of the reference parameter set referenced by the slot format table.

However, when a default reference parameter set is defined and a slot format table based on the default reference parameter set is used, the network may not separately notify the UE of the reference parameter set.

For example, a default reference parameter set may be defined as follows, but is not limited thereto. (i) The smallest parameter set among the parameter sets configurable for the UE may be selected as the default reference parameter set. For example, assuming that the SCS of the parameter set configurable for the UE is 15, 30, 60 and 120kHz, the network may define 15kHz as the default reference parameter set. (ii) The largest parameter set among the parameter sets that may be configured for the UE may be selected as the default reference parameter set. For example, assuming that the SCS of the parameter set configurable for the UE is 15, 30, 60 and 120kHz, the network may define 120kHz as the default reference parameter set. (iii) As another example, 15kHz may be fixed as a default reference parameter set.

-option 2: as another example, the network may define a set of parameters for the control channel that are used to indicate an index in a slot format table configured for the UE as a set of reference parameters.

-option 3: as another example, a parameter set of a band in which a corresponding slot format is actually to be used may be defined as a reference parameter set.

3. Inherit the early SFI

The method of converting the slot format of the SCS depending on the UE by the UE when the slot format is transmitted based on the reference SCS (or the reference parameter set) has been described above.

When the UE changes carriers after applying the specific SFI and a parameter set of the changed BWP/carrier is different from a previous BWP/carrier, whether the UE re-applies the specific SFI may be issued according to the aforementioned slot format conversion rule.

-option 1: for example, when the parameter set of the changed BWP/carrier is different from the previous BWP/carrier, the UE may ignore the previously indicated slot format and may perform a backoff operation from the time point of the BWP/carrier change until the next SFI.

-option 2: as another example, when the parameter set of the changed BWP/carrier is different from the previous BWP/carrier, the UE may start from the time point of changing the BWP/carrier until the next SFI application of the slot format modified according to the changed parameter set. However, in case of a format that is not supported by the modified slot format, the UE may disregard the corresponding slot format and may perform a fallback operation.

4. Inheriting an early SFI in beam switching

Multiple beams may be configured for the UE and beam switching may occur as desired. As such, when switching beams, the UE may need to choose whether to apply the existing applied SFI to the new beam without change.

-option 1: the UE may ignore the existing slot format from the point of time when the beam switching occurs until the next SFI, and may perform a backoff operation.

-option 2: the UE may follow the existing slot format from the point in time when the beam switching occurs until the next SFI. When the parameter set for handover is different from the previous beam, the UE may apply the slot format modified according to the changed parameter set. However, in case of a format that is not supported by the modified slot format, the UE may disregard the corresponding slot format and may perform a fallback operation.

5. Defining reference parameter sets

In order to perform the method of modifying the slot format according to the parameter set as described above, it may be important to define a reference parameter set. Applying the aforementioned slot format modification rule may not be problematic when the set of parameters for the scheduling/scheduled carrier is the same in cross-carrier scheduling. However, a plurality of BWPs may be configured for each carrier, and may be different for each BWP parameter set.

When an SFI is defined/signaled for each cell (i.e., carrier) in a group-common PDCCH transmitted through a PCell, a reference parameter set of the SFI may need to be defined for each cell.

For example, in case of PCell, a parameter set for transmitting a group common PDCCH may correspond to a reference parameter set.

In the case of an SCell, the following options may be considered.

-option 1: the slot format may be indicated based on the parameter set of the currently active BWP.

-option 2: a parameter set of a first activated BWP in an SCell may be defined as a reference parameter set of the SCell.

-option 3: a parameter set for a default BWP for the SCell may be defined as a reference parameter set for the SCell.

<Multi-band slot format indication>

The slot format indication may be mainly used in a TDD environment, but may be used to indicate a slot format in an FDD band. Each band of the FDD may be typically fixed as D or U, but the network may allow each band of the FDD to be used for other purposes by "unknown". In this case, the network needs to indicate the slot formats of the D band and the U band in FDD, and thus, a method is needed.

In an LTE-NR coexistence environment, the network may allocate a Supplemental Uplink (SUL) that temporarily uses the LTE UL band to NR users to be used for an additional UL band of NR users. In this case, when the NR user operates in TDD, the network needs to indicate the slot format of the NR TDD band and the slot format of the SUL at the same time.

This method of simultaneously indicating the slot formats of two or more bands is described below.

1. List of documents

For example, a table in which slot formats of two or more bands (e.g., BWPs) are consecutively disposed in one row may be defined/configured.

Fig. 3 illustrates a combination of slot formats according to an embodiment of the present invention.

For example, when the slot format of band 1 is denoted as SF1 and the slot format of band 2 is denoted as SF2, the slot format set transmitted by the network to the UE may have the form of SF1+ SF2+.. 9. The slot format group may be an entry in a slot format table and the entries may be grouped to configure the slot format table.

The network may configure a combination of slot formats corresponding to a slot format table for the UE via higher layer signaling, and then may inform the UE of the slot format combination of a specific entry through the group common PDCCH.

Furthermore, even in one entry, the SCS may be different for each band. Therefore, the number of slots may be different for each SF.

The slot format table may be configured in such a manner that slots corresponding to the same specific duration are successively deployed among slot formats of respective bands and then slots corresponding to the next same duration are successively deployed.

For example, it may be assumed that the parameter set for band 1 is a 60kHz SCS and the parameter set for band 2 is a 15kHz SCS. Band 1 may have 4 slots within 1ms and band 2 may have 1 slot within 1ms. When the duration of the slot format to be notified to the UE by the network is 2ms, the number of slots of band 1 is 8 within 2ms, and the number of slots of band 2 is 2 within 2 ms. In this case, the network may deploy a 2-band slot format in the form of 1 slot of 4 slots of band 1+ 1 slot of band 2+ 4 slots of band 1+ 1 slot of band 2.

For example, the network may deploy 1 slot of 4 slots + 1 slot with 2, which corresponds to the same duration of 1ms, and then, may deploy 4 slots with 1+ 1 slot with 2, which corresponds to the next duration of 1ms.

Such slot format deployment may be performed regardless of the number of bands.

Fig. 4 illustrates a combination of slot formats according to another embodiment of the present invention. For convenience, it may be assumed that the number of bands is 2 or 3 in fig. 4. For example, in the case of entry 2, band 1, band 2, and band 3 have the same SCS. In the case of entry 4, it may be assumed that the SCS of band 2 is twice the SCS of band 1, and that the SCS of band 1 is twice the SCS of band 3.

The method shown in fig. 3 or fig. 4 may be used when the network indicates a time slot of the same duration corresponding to multiple bands at a time.

2. Multi-list

Fig. 5 and 6 illustrate a combination of slot formats according to another embodiment of the present invention.

The slot formats of the multiple bands may be consecutively disposed in a column, as illustrated in fig. 3 or fig. 4. However, according to another embodiment of the present invention, one column may be defined for each band, and a slot format may be indicated.

3. Multi-band supporting multiple parameter sets

The method of indicating the slot form of all parameter sets to be supported by one band through one slot format table has been described above with respect to the embodiment related to table 4 above. The method of indicating the slot format of a plurality of bands by one slot format table has been described with respect to the embodiments related to fig. 3 to 6.

The above embodiments may also be combined to consider a method of simultaneously indicating the slot formats of all parameter sets to be supported for each of a plurality of bands. For example, the embodiment may be formed by combining the embodiment related to table 4 above and the embodiments related to fig. 3 to 6.

For example, a column may be defined for each band and a sub-column may be defined for the parameter sets of the respective band, and thus, the network may indicate the slot format of the respective parameter sets of the plurality of bands in one row at a time.

Fig. 7 illustrates a combination of slot formats according to an embodiment of the present invention.

In fig. 7, as an example, the number of bands and the number of parameter sets of each band may be changed. As the number of bands and/or the number of parameter sets for each band increases, the size of the illustrated slot format table may also increase.

4. Reference parameter set setting

When one table is used to indicate the slot formats of a plurality of bands, the parameter set of each band needs to be considered. This is because the method of indicating the slot format of each band is changed according to the determined reference parameter set. Each band may be, for example, any one of a DL band, a UL band, a SUL band, and a TDD band, but is not limited thereto.

The considered method is described below.

-option 1: the slot format indicated by the slot format table may be a slot format according to a parameter set of each band. For example, when band 1 is the SCS of 30kHz and band 2 is the SCS of 15kHz, the slot format of each band may be defined as the slot format for the SCS of 30kHz and the slot format for the SCS of 15 kHz. When the slot format of 30kHz SCS/15kHz SCS is inserted into the table, either the slot format of 30kHz SCS/15kHz SCS or a combination of slot format columns for each band may be deployed.

-option 2: the slot format may be indicated based on a minimum set of parameters among the sets of parameters for the multiple bands. The UE may modify the slot format indicated according to the parameter set of each band using the slot format extension method described above.

-option 3: the slot format may be indicated based on a largest parameter set among the plurality of parameter sets configured for the band.

-option 4-1: the reference parameter set may be separately defined, and the slot format of each band may be indicated based on the reference parameter set.

-option 4-2: the reference parameter set may be defined separately, and only some of the band slot formats may be indicated based on the reference parameter set. The slot format of the parameter set according to the corresponding band may be indicated for the other bands. For example, some bands to which the reference parameter set is applied may be at least one of a DL band, a UL band, a SUL band, and a TDD band.

The reference parameter set in options 4-1 and 4-2 may be determined using the aforementioned method of determining a reference parameter set.

Although the proposed methods can be implemented independently, some of the proposed methods can be combined (or integrated). It may be adjusted that information indicating whether the proposed method is applied (or information on the rules of the proposed method) is sent to the UE by the base station in a predefined signal (e.g., a physical layer signal or a higher layer signal).

<Group common PDCCH>

Hereinafter, the content and the expected payload size of DCI transmitted through the group common PDCCH are described.

A signaling method of the group common PDCCH is now described. Examples of the signaling method may include a method of allocating and transmitting reserved resources and a method of configuring and transmitting a search space.

When information on a slot type is transmitted through a group common PDCCH, whether a method of transmitting a slot type to a UE operating with a plurality of CCs is effective is described below.

1. Content of group common PDCCH

(1) Time slot format indication

The group common PDCCH may be used to inform the UE of the slot format. The slot format may be indicated in various types. The payload size of the group common PDCCH may vary according to the type of slot format indicated.

The size of 1 slot (e.g., length in time domain) may be changed according to the parameter set. The number of time slots configuring 1 time slot may be changed according to the parameter set.

(i) Time slot type

The group common PDCCH may indicate a type of at least one slot.

For example, the time slots may be classified as shown in the following table 5, but are not limited thereto.

[ Table 5]

Time slot	Description of the invention
		D alone	Time slot in which only downlink is supported
U only	Time slot in which only the uplink is supported
		D-center	Time slot in which downlink is supported in most symbols of configuration time slot
U-center	Time slot in which uplink is supported in most symbols of configuration time slot
		Data Region (DR)	Time slots for other data but not for UE-specific data, e.g. in MBSFN sub-frames
Retention	Time slots occupied by the network but not specifically used by the UE when necessary

In case of D-center and U-center slot types, it may be indicated only whether the corresponding slot is D-center or U-center, and thus the configuration of actual symbols (e.g., downlink and uplink) included in the corresponding slot needs to be predefined. The DL/UL portion in the D/U-center slot may be predefined or may be configured by the network. Depending on the DL/UL resource configuration, one or more D/U-centric modes may exist.

The use of reserved/DR slots may or may not be predefined. For example, the use of reserved/DR slots may be predefined via system information, higher layer indications, etc. When the use of the reserved/DR slot is undefined, the network may inform the UE of the use when the slot type is indicated through the group common PDCCH, or may not indicate the use if the UE does not need to know the use of the reserved/DR slot. The reserved resources may be configured separately from the slot type. For example, the network may configure the reserved resources via dynamic/semi-static signaling.

(ii) Slot type mode

The group common PDCCH may indicate a type of a plurality of slots. For example, the group common PDCCH may indicate at least one of combinations of a plurality of slots. When the network indicates respective types of a plurality of slots one by one, a payload size of the group common PDCCH increases and signaling overhead increases may be inefficient. Accordingly, the number of slots to be indicated and each slot type may be defined as one mode, and the network may inform the UE of the index of the mode through the group common PDCCH.

Multiple slot type patterns may be defined. For example, the slot type pattern may be defined as [ periodicity/slot type or pattern or set of slot types ], but is not limited thereto.

Fig. 8 illustrates a pattern of a slot format according to an embodiment of the present invention. In fig. 8, DU refers to symbols, and half of them are D symbols and the other half are U symbols.

In case of the FDD system, a slot corresponding to D in fig. 8 may correspond to a slot format of a DL band (e.g., DL BWP) and a slot corresponding to U in fig. 8 may be interpreted as a slot format of an UL band (e.g., UL BWP). For example, the configuration of the mode obtained by the base station combining the D slot format and the U slot format for the UE may be interpreted as the configuration of the mode obtained by the base station combining the slot format of the DL band (e.g., DL BWP) and the slot format of the UL band (e.g., UL BWP) for the UE.

A plurality of slot type modes to be used in the respective cells or the respective groups may be defined/configured, and the network may inform the UE of the mode to be used in the plurality of slot type modes. For example, the subset may be signaled to the UE among the defined patterns. Fig. 8 illustrates a total of 12 modes, and in this case, information indicating that modes #5 to #8 defined using a 2 slot part among the 12 modes are available may be signaled to the UE. In this case, 4 patterns #5 to #8 may be re-indexed and may be considered as patterns #1 to #4.

In this way, when the UE is notified of the subset of slot type patterns in advance, the network can sequentially transmit only the indexes of the re-indexed patterns to the group common PDCCH. Accordingly, signaling overhead of the group common PDCCH may be reduced. For example, the group common PDCCH may not necessarily cover all 12 modes inevitably, and may be configured to cover 4 modes, and in this case, the payload size of the group common PDCCH may be reduced.

The information on the subset of the slot type pattern may be transmitted to the UE through a MAC Control Element (CE) or may be transmitted through a group common PDCCH. Alternatively, the network may predefine the period of time that the mode is indicated by the system information. Alternatively, the information about the subset of slot type patterns may be sent via UE-specific higher layer signaling.

The pattern for a long period of time may be defined in the form of repeating a pattern for a short period of time. In this case, in the case where the network needs to indicate both slot formats at the same time, the mode information on the long period may be advantageously replaced with the mode information on the short period.

(iii) Indication of symbol unit

According to another embodiment of the present invention, the group common PDCCH may indicate a slot type in a symbol unit of a configuration slot. For example, resource types such as D/U/reserved in table 6 below may be applied in symbol units.

Table 6 below shows an exemplary slot format under the assumption that 1 slot includes 7 symbols.

[ Table 6]

Time slot format

Symbol 0

Symbol 1

Symbol 2

Symbol 3

Symbol 4

Symbol 5

Symbol 6

1

D

D

D

D

U

U

U

2

D

D

R

R

R

R

U

3

D

U

U

U

U

U

U

4

D

D

DR

DR

DR

DR

DR

…

(iv) Symbol pattern

Although the method of indicating the index of the slot mode through the group common PDCCH has been described above, the group common PDCCH may indicate the index of the symbol mode according to another embodiment of the present invention.

[ Table 7]

Table 7 below shows an exemplary symbol pattern (or slot format) assuming that 1 slot includes 7 symbols.

[ Table 7]

Time slot format

Symbol 0

Symbol 1

Symbol 2

Symbol 3

Symbol 4

Symbol 5

Symbol 6

1

D

D

D

R

R

U

U

2

D

DR

DR

DR

U

U

U

3

R

R

R

R

U

U

U

…

(2) Other information

The group common PDCCH may include other information in addition to slot format information.

(i) And (3) punching indication: the group common PDCCH may include puncturing information for URLLC. The period used as URLLC may be indicated in units of slots or in units of symbols.

(ii) Semi-static resource information: the group common PDCCH may include information on semi-static resources such as CSI-RS. For example, the group common PDCCH may indicate information on what is the corresponding semi-static resource, or when the corresponding semi-static resource has a period, information on the period, transmission duration, and the like.

2. Transmission of group common PDCCH

As a method of transmitting the group common PDCCH through the network, a method of configuring and transmitting a search space for the group common PDCCH and a method of securing and transmitting reserved resources for the group common PDCCH may be considered.

(1) Transmission using group common PDCCH reserving resources

The network may previously secure resources (e.g., REs, REGs, RBs, and CCEs) in which the group common PDCCH is to be transmitted.

The group common PDCCH may also be a control channel and may therefore be deployed on CORESET. In addition, it may be desirable to reserve locations of resources for group common PDCCH deployments to minimize blocking of other control channels. In particular, the group common PDCCH may maximally avoid blocking the CSS.

When defining the location in the logical domain in which the control channel is transmitted, the logical location of the reserved resources for the group common PDCCH may immediately precede or follow the CSS. Alternatively, the reserved resource for the group common PDCCH may be positioned at the last part of the CORESET, or may be positioned to be spaced apart from the start index or the end index of the CSS by a predetermined offset. In this case, the offset may be different for each cell/group. The offset may be notified to the UE via system information, higher layer signaling, and the like.

Alternatively, resources for a group common PDCCH may be deployed in the CSS. In this case, the size of the group common PDCCH may be equal to or smaller than the size of the smallest candidate among the control channel candidates in the CSS. In this case, reserved resources for the group common PDCCH may be included in candidates of the CSS, and in this regard, the UE may basically perform blind Detection (DB) on the CSS regardless of whether the group common PDCCH is detected in a reserved resource group in the CSS.

The location of the reserved resources for the group common PDCCH may be notified to the UE via system information, higher layer signaling, or the like. When group common PDCCH is transmitted through candidates on the CSS, the number of available candidates may be reduced to transmit PDCCH in the CSS (e.g., common control information instead of group common PDCCH), which results in a similar result to CSS blocking. Accordingly, when the group common PDCCH is configured in the CSS, the UE may assume that a candidate to which the group common PDCCH is mapped is not used as a CSS candidate for another channel, and may assume that the candidate is an invalid candidate. The UE may skip blind detection of invalid candidates and may proceed to the next candidate. In addition, similar to the general PDCCH, the group common PDCCH may be defined to be transmitted using the CSS, and in this case, a general blind detection procedure on the CSS may also be performed on the group common PDCCH in the same manner.

Fig. 9 illustrates reserved resource allocation for a group common PDCCH according to an embodiment of the present invention. The group common PDCCH may be mapped to a block indicated by a dotted line in fig. 9.

Fig. 9 (a) illustrates a case where reserved resources for a group common PDCCH are allocated to the first candidate. Accordingly, the UE may omit blind detection of a general PDCCH for a corresponding block.

Fig. 9 (b) illustrates a case where reserved resources for the group common PDCCH are allocated to the next part of the last candidate. Fig. 9 (c) illustrates a case in which reserved resources for the group-common PDCCH are allocated to a position having a predetermined offset from the last candidate.

(2) Transmission of group common PDCCH through search space

The network may configure a search space in which the group common PDCCH is to be transmitted, and the UE may perform blind detection in the corresponding search space to detect the group common PDCCH.

(i) Using G-RNTI

The search space in which the group common PDCCH is to be transmitted is referred to as GSS. A Radio Network Temporary Identifier (RNTI) required to detect a group common PDCCH in the GSS is called G-RNTI. For example, the CRC of the group common PDCCH may be scrambled or masked by the G-RNTI.

1 UE may have one or more G-RNTIs. For example, one UE may be configured with one or more GSSs. GSS can be defined regardless of its number.

GSS in CSS

For example, the network may randomly deploy GSSs in CSSs. To deploy GSS in CSS, the size and/or number of candidates of GSS may be equal to or smaller than the size and/or number of candidates of CSS. The candidates for GSS may be deployed continuously or may be distributed and deployed separately.

When the size of the candidate of the GSS is the same as the size of the candidate of the CSS, the UE needs to additionally perform CRS checking only on the GSS (e.g., CRC checking through R-RNTI) while performing blind detection on the CSS, and thus, the problem in the overhead of additional blind detection due to additional deployment of the GSS can be overcome.

FIG. 10 illustrates GSSs deployed in CSSs, according to an embodiment of the invention.

An environment in which the size of the largest candidate among the GSS candidates is equal to or smaller than the size of the smallest candidate of the CSS and the number of GSS candidates is equal to or smaller than half the number of CSS candidates may be considered.

GSS in CORSET

Similar to the USS, the network may use the G-RNTI to randomly deploy the GSS on CORESET according to a hash function. The GSS candidates may be deployed continuously or may be distributed and deployed individually.

(ii) Without G-RNTI

GSS in CSS

The network may deploy GSS in CSS. This embodiment is partly similar to the method of deploying GSSs in CSSs described above, but according to this embodiment the network may form a GSS and may deploy a GSS in a CSS to reduce the likelihood of blocking control channels to be transmitted in the CSS. The size/number of GSSs may be equal to or smaller than the size/number of CSS candidates.

When there is no G-RNTI, the position of the GSS candidate needs to be determined. When the size of the candidate of the GSS is the same as the size of the candidate of the CSS, the UE needs to additionally perform CRS checking on the GSS while performing blind detection on the CSS, and thus, additional blind detection due to additional deployment of the GSS may be reduced.

The location of the GSS candidate to be deployed in each CSS candidate may be defined by system information or higher layer signaling. The candidates for GSS may be deployed continuously or may be distributed or deployed individually.

Fig. 11 illustrates GSS candidates having fixed positions in the CSS according to an embodiment of the invention.

When the GSS candidate and the CSS candidate have the same size, the starting index of the CCE corresponding to the even-numbered or odd-numbered candidate of the CSS may be used as the starting index of the CCE candidate.

When the number of CCEs of the GSS candidate is less than the number of CCEs of the CSS candidate, the index of the even-numbered or odd-numbered CCE among the even-numbered or odd-numbered candidates of the CSS may be used as the starting index of the CCE of the GSS candidate.

GSS in CORSET

When the GSS is continuously configured without a separate RNTI like the CSS of the LTE, the start index of the GSS may be given by applying an offset to the start index or the end index of the CSS.

The offset may be different for each cell/group. The offset may be signaled to the UE via system information, higher layer signaling, etc.

When the group-common PDCCH is transmitted to a part of the CSS (when the GSS candidate is fixed or not fixed), the UE may assume that the group-common PDCCH is transmitted only in a slot or a micro-slot in which the CSS is transmitted.

When the group common PDCCH is transmitted to the CSS and the separate resource, the interval and resource of the slot in which the group common PDCCH is to be transmitted or the micro slot may be separately configured from the CSS.

When a size of Downlink Control Information (DCI) of the group-common PDCCH is different from the DCI transmitted in the CSS, a set of slots to be monitored by the UE for the group-common PDCCH may be different from the CSS monitoring set. More generally, the set of slots or minislots monitored by the UE may be configured differently for each RNTI, or the set of slots or minislots monitored by the UE may be configured differently for each DCI size.

3. Multiple divisionTime slot format indication of volume carrier

When the UE uses multiple carriers (e.g., carrier aggregation), the network may inform the UE of the slot format to be used in each carrier.

(1) Transmission of group common PDCCH for multiple CCs

The network may send a group common PDCCH for each CC to send a slot format indication for each CC. Alternatively, the network may indicate the slot formats of all CCs through one primary CC (PCC).

When the number of CCs used by the UE is high, the network may group the CCs into a plurality of groups and define a PCC for each group. The network may indicate the slot format of the CCs in the corresponding group through the PCC of each group.

A method of grouping CCs is described below.

(i) CC with same slot format

The network may group CCs having the same slot format into the same group. In this case, the network may indicate the slot format of only one CC without indicating the slot format for each CC. Thus, the amount of information required for slot format indication and signaling overhead may be reduced.

(ii) CC with same parameter set

The network may group CCs with the same set of parameters into the same group. In this case, all CCs in the group may have the same slot length. Therefore, when indicating slot formats with the same duration, the network may need to take into account the difference in slot index due to the parameter set difference.

When the network transmits slot format information on multiple CCs, the payload size of the group common PDCCH may be significantly increased. The maximum size of the payload of the group common PDCCH is [ the number of slot format information × CC of 1CC ], and thus, it may be difficult to increase the size of the slot format information of 1 CC. The slot format information in units of symbols requires a large amount of information, and thus, the slot format indication to be used when configuring a UE with multiple CCs may be a slot type indication or a slot type mode indication.

A payload size of a group common PDCCH for a plurality of CCs may be determined according to whether the CCs are grouped. When grouped CCs have the same set of parameters, there is no problem with the same indication slot type, but when individual CCs need to receive indications of different slot types, it may be difficult to support multiple CCs with one slot format indicator.

When the slot format is indicated by the slot type mode, a problem may occur when periods of the slot format to be indicated by CCs in the group are different. As a case where the length of the slot format to be received via the indication is different for each CC, when the UE receives a slot format of a long period, the slot format may be converted into a slot format of a short period. Alternatively, the network may perform the indication of the plurality of slot format periods by one slot format indicator.

For example, the pattern of the long slot period may be defined by repeating the pattern of the short slot period.

As another example, a pattern of short slot periods may be predefined in association with a pattern of long slot periods. Even if the UE receives a pattern of a long slot pattern, the UE may use a pattern of a short slot period that matches the corresponding pattern.

A more detailed example is described below with reference to fig. 12 and 13. Fig. 12 and 13 illustrate slot patterns of a plurality of CCs according to an embodiment of the present invention.

In fig. 12 and 13, it is assumed that CCs in a group include a CC receiving an indication of 4 slots as a slot mode period and a CC receiving an indication of 2 slots as a slot mode period.

Referring to fig. 12, the pattern of 4 slot periods may be defined in a form in which the pattern of 2 slot periods is repeated twice.

Referring to fig. 13, a 2-slot period pattern associated with a 4-slot period pattern may be defined.

When parameter sets are different for respective CCs but the CCs have the same duration for the slot mode indication, the slot mode period may be determined according to the difference of the parameter sets. For example, a pattern of a short slot period may be used for a CC having a short SCS, and a pattern of a long slot period defined by the pattern of the short slot period may be used for a CC of a large SCS. This is because the number of slots of the CC having the large SCS is greater than that of the CC having the small SCS in the case of the same duration.

Fig. 14 illustrates a slot pattern of a plurality of CCs according to another embodiment of the present invention. It can be assumed that the 4-slot mode is a mode of CC using SCS of 30kHz and the 2-slot mode is a mode of CC using SCS of 15 kHz.

In (a) of fig. 14, the pattern of the 4-slot period may be defined in a form in which the pattern of the 2-slot period is repeated twice.

In (b) of fig. 14, the pattern of the 4-slot period and the pattern of the 2-slot period may be associated with each other.

Thus, the slot pattern of multiple CCs using different parameter sets may be indicated by one slot format indication.

When the slot formats of the plurality of carriers are indicated by one group common PDCCH, the period of the slot format of each carrier may be matched based on the carrier transmitting the group common PDCCH. When the period of the slot format of each carrier is shorter than the reference period, a new configuration set according to the repetition pattern/period may be given. The case where the period of the slot format of the specific carrier is longer than the reference period can be handled in a similar manner.

(2) Time slot format indicating method

The network-based CC index and the UE-based CC index may be different. Therefore, when the slot format of the CC is indicated, the network may consider the CC index to be different.

For example, when the network-based CC is NCC and the UE-based CC is UCC, NCC 1 may be classified into a plurality of UCCs (e.g., UCC 1 to UCC n). When the network indicates the UCC-based slot format as a reference of the UE, the UE can appropriately recognize the indicated information.

The relationship between NCC and UCC may be UE-specific to transmission. For example, when the number of CCs configured as NCC is m and the number of CCs configured as UCC is n, the relationship between NCC and UCC may be defined by the network. The relationship between NCC and UCC may be signaled via MAC CE, system information, or group common PDCCH.

Table 8 below shows an example of the relationship between NCC and UCC with respect to one UE.

[ Table 8]

(i) Time slot format indication on the network side

The network may indicate the slot format based on the index of the NCC. Upon receiving the indication of the slot format based on the index of the NCC, the UE may find an index of the UCC of the UE corresponding to the NCC and may use the indicated slot format as the corresponding slot format of the UCC of the UE.

(ii) Time slot format indication on the part of UE

The network may indicate the slot format based on the index of the UCC. The network may define and indicate the slot format as many as the number UCC _ max of UCCs of a UE having the largest number of UCCs among UEs belonging to the same group. The UE having the UCCs whose number is less than UCC _ max may selectively acquire only as many indication information as the number of UCCs of the UE, and may determine a slot format of each UCC of the UE.

When mapping between NCC and UCC is performed in a similar manner for a plurality of UEs, it may be easy to indicate a slot format based on the UCC index.

Fig. 15 illustrates a flow of a method of transmitting and receiving Downlink Control Information (DCI) according to an embodiment of the present invention. Fig. 15 illustrates an example of the foregoing method, and therefore, a repetitive description of the above description may not be given here.

Referring to fig. 15, the base station may transmit information on a reference subcarrier spacing (SCS) among a set of parameters for the SCS (1505). The information on the reference SCS may be sent via higher layer signaling.

The base station may generate DL control information including information on a slot format (1510).

The base station may transmit DL control information to a UE group including the UE through a UE group common Physical Downlink Control Channel (PDCCH) (1515).

The UE may acquire information on the slot format from the DL control information (1520).

The DL control information may indicate a slot format based on the reference SCS. When the SCS of the UE is different from the reference SCS, the UE may convert the slot format of the reference SCS according to the SCS of the UE.

The duration of 1 slot may vary according to the SCS. The reference SCS may be configured to be equal to or less than the SCS of the UE in such a manner that the duration of 1 slot based on the reference SCS is equal to or greater than the duration of 1 slot of the UE based SCS.

When the SCS of the UE is M times the reference SCS, the UE may interpret the 1 time slot based on the reference SCS as M consecutive time slots of the UE-based SCS.

The UE may determine whether each of a plurality of symbols included in a respective slot corresponds to a downlink (D), an uplink (U), or a flexible (X) based on the information about the slot format. When the SCS of the UE is M times the reference SCS, the UE may interpret one D, U, or X symbol based on the reference SCS as M D, U, or X symbols of the UE-based SCS.

The information on the slot format may indicate at least one of slot format combinations configured in the UE.

A plurality of frequency bands may be configured for the UE, and each slot format combination may be obtained by combining a plurality of slot formats of the plurality of frequency bands.

Each slot format combination may be obtained by combining a slot format for a DL band and a slot format for an UL band. Alternatively, each slot format combination may be obtained by combining a slot format for a new radio access technology (NR) band and a slot format for a Long Term Evolution (LTE) band.

A slot format combination configured for the UE may be received via higher layer signaling and may be a subset of a plurality of slot format combinations supported in the wireless communication system. For example, the slot format of the UL band (e.g., UL BWP) and the slot format of the DL band (e.g., DL BWP) may correspond to one slot format combination. Alternatively, the slot format of BWP on the NR band and the slot format of BWP (e.g., SUL) on the LTE band may correspond to one slot format combination. The base station may configure at least one slot format combination among the plurality of slot format combinations via RRC signaling for the UE. Then, the base station may indicate at least one of the slot format combinations configured for the UE RRC through DCI transmitted through the group common PDCCH.

Fig. 16 is a block diagram illustrating structures of a Base Station (BS) 105 and a UE 110 in the wireless communication system 100 according to an embodiment of the present invention. The BS 105 may be referred to as an eNB or a gNB. UE 110 may be referred to as a user terminal.

Although one BS 105 and one UE 110 are illustrated for simplicity of the wireless communication system 100, the wireless communication system 100 may include one or more BSs and/or one or more UEs.

The BS 105 may include a transmit (Tx) data processor 115, a symbol modulator 120, a transmitter 125, a transmit/receive antenna 130, a processor 180, a memory 185, a receiver 190, a symbol demodulator 195, and a receive (Rx) data processor 197.UE 110 may include a Tx data processor 165, a symbol modulator 170, a transmitter 175, a transmit/receive antenna 135, a processor 155, a memory 160, a receiver 140, a symbol demodulator 155, and an Rx data processor 197. In fig. 12, although one antenna 130 is used for the BS 105 and one antenna 135 is used for the UE 110, each of the BS 105 and the UE 110 may include a plurality of antennas as necessary. Accordingly, the BS 105 and the UE 110 according to the present invention support a Multiple Input Multiple Output (MIMO) system. The BS 105 according to the present invention can support both a single user-MIMO (SU-MIMO) scheme and a multi-user-MIMO (MU-MIMO) scheme.

In the downlink, the Tx data processor 115 receives traffic data, formats the received traffic data, encodes the formatted traffic data, interleaves the encoded traffic data, and modulates the interleaved data (or performs symbol mapping on the interleaved data) such that it provides modulation symbols (i.e., data symbols). A symbol modulator 120 receives and processes the data symbols and pilot symbols such that it provides a stream of symbols.

The symbol modulator 120 multiplexes data and pilot symbols and transmits the multiplexed data and pilot symbols to the transmitter 125. In this case, each transmit (Tx) symbol may be a data symbol, a pilot symbol, or a value of a null signal (null signal). In each symbol period, pilot symbols may be continuously transmitted during each symbol period. The pilot symbols may be FDM symbols, OFDM symbols, time Division Multiplexed (TDM) symbols, or Code Division Multiplexed (CDM) symbols.

Transmitter 125 receives the stream of symbols, converts the received symbols into one or more analog signals, and otherwise conditions (e.g., amplifies, filters, and upconverts) the one or more analog signals such that it generates a downlink signal suitable for transmission of data over the RF channel. The downlink signal is then transmitted through the antenna 130 to the UE.

The configuration of the UE 110 will be described in detail hereinafter. The antenna 135 of the UE 110 receives a DL signal from the BS 105 and transmits the DL signal to the receiver 140. Receiver 140 performs conditioning (e.g., filtering, amplification, and frequency down-conversion) of the received DL signal and digitizes the conditioned signal to obtain samples. A symbol demodulator 145 demodulates received pilot symbols and provides the results of the demodulation to a processor 155 for channel estimation.

The symbol demodulator 145 receives a frequency response estimation value for downlink from the processor 155, demodulates the received data symbols, obtains data symbol estimation values (estimation values indicating the transmitted data symbols), and provides the data symbol estimation values to the Rx data processor 150. The Rx data processor 150 performs demodulation (i.e., symbol demapping) of the data symbol estimation values, deinterleaves the demodulation results, decodes the deinterleaved results, and restores the transmitted traffic data.

The processes of the symbol demodulator 145 and the Rx data processor 150 are complementary to those of the symbol modulator 120 and the Tx data processor 115 in the BS 205.

The Tx data processor 165 of the UE 110 processes traffic data in uplink and provides data symbols. A symbol modulator 170 receives and multiplexes the data symbols and modulates the multiplexed data symbols so that they can provide a stream of symbols to a transmitter 175. Transmitter 175 obtains and processes the stream of symbols to generate an Uplink (UL) signal, and the UL signal is transmitted by antenna 135 to BS 105. The transmitter and receiver of the UE/BS may be implemented as a single Radio Frequency (RF) unit.

BS 105 receives the UL signal from UE 110 through antenna 130. The receiver processes the received UL signal to obtain samples. A symbol demodulator 195 then processes the symbols and provides pilot symbols and data symbol estimates received via the uplink. The Rx data processor 197 processes the data symbol estimates and recovers traffic data received from the UE 110.

The processor 155 or 180 of the UE 110 or the BS 105 commands or instructs the operation of the UE 110 or the BS 105. For example, the processor 155 or 180 of the UE 110 or the BS 105 controls, regulates, and manages the operation of the UE 210 or the BS 105. Each processor 155 or 180 may be connected to a memory unit 160 or 185 for storing program codes and data. The memory 160 or 185 is connected to the processor 155 or 180 so that it can store an operating system, application programs, and general files.

The processor 155 or 180 may also be referred to as a controller, microcontroller, microprocessor, microcomputer, or the like. Meanwhile, the processor 155 or 180 may be implemented by various means, for example, hardware, firmware, software, or a combination thereof. In a hardware configuration, the method according to an embodiment of the present invention may be implemented by the processor 155 or 180, for example, one or more Application Specific Integrated Circuits (ASICs), digital Signal Processors (DSPs), digital Signal Processing Devices (DSPDs), programmable Logic Devices (PLDs), field Programmable Gate Arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, and the like.

In a firmware or software configuration, the method according to an embodiment of the present invention may be implemented in the form of a module, a procedure, a function, etc. performing the above-described functions or operations. Firmware or software implemented in the present invention may be included in the processor 155 or 180 or the memory unit 160 or 185 so that it can be driven by the processor 155 or 180.

The radio interface protocol layers among the UE 110, the BS 105, and the wireless communication system (i.e., network) may be classified into a first layer (L1 layer), a second layer (L2 layer), and a third layer (L3 layer) based on the lower three layers of an Open System Interconnection (OSI) reference model widely known in the communication systems. A physical layer belonging to the first layer (L1) provides an information transfer service through a physical channel. A Radio Resource Control (RRC) layer belonging to the third layer (L3) controls radio resources between the UE and the network. The UE 110 and the BS 105 may exchange RRC messages with each other through the wireless communication network and the RRC layer.

The above-described embodiments correspond in a prescribed form to combinations of elements and features of the present invention. Also, unless explicitly mentioned otherwise, each element or feature can be considered optional. Each element or feature can be implemented in a form that cannot be combined with other elements or features. Further, by partially combining elements and/or features, embodiments of the present invention can be realized. A series of operations explained for each embodiment of the present invention can be modified. Some configurations or features of one embodiment can be included in another embodiment or can replace corresponding configurations or features of another embodiment. Also, it is obviously understood that the embodiments are configured by combining claims which are not explicitly cited in the appended claims together, or can be included as a new claim by modification after filing an application.

While the invention has been described and illustrated with reference to the preferred embodiments thereof, it will be apparent to those skilled in the art that various modifications and variations can be made therein without departing from the spirit and scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

[ Industrial Applicability ]

As described above, the present invention can be applied to various wireless communication systems.

Claims (13)

1. A method of receiving downlink, DL, control information by a user equipment, UE, in a wireless communication system, the method comprising:

receiving first information on a reference subcarrier spacing (SCS);

receiving DL control information through a PDCCH (physical Downlink control channel) of a UE group;

obtaining second information on a slot format related to the reference SCS from the DL control information; and

applying the time slot format to a plurality of time slots of a first SCS used by the UE based on the first SCS, which is different from the reference SCS, wherein the plurality of time slots of the first SCS correspond to time slots of the reference SCS,

wherein the reference SCS is smaller than the first SCS of the UE, and

wherein a duration of one time slot of the reference SCS is greater than a duration of each of the plurality of time slots of the first SCS of the UE.

2. The method of claim 1, wherein receiving first information regarding the reference SCS comprises:

receiving the first information regarding the reference SCS via higher layer signaling.

3. The method of claim 1, wherein the first SCS of the UE is M times larger than the reference SCS, and

wherein the plurality of time slots of the first SCS consists of M consecutive time slots of the first SCS corresponding to time slots of the reference SCS.

4. The method of claim 3, wherein a slot of the reference SCS includes a first plurality of symbols,

wherein each of the plurality of slots of the first SCS of the UE includes a second plurality of symbols,

wherein the M consecutive symbols of the first SCS correspond to one symbol of the reference SCS, and

wherein applying the slot format to the plurality of slots of the first SCS comprises: for each of the first plurality of symbols in the slot of the reference SCS,

determining that the symbols of the reference SCS correspond to one of a downlink D, an uplink U, or a flexible X based on the second information on the slot format; and

determining that the M consecutive symbols of the first SCS each correspond to the one of D, U, or X.

5. The method of claim 1, wherein the second information about the slot format indicates at least one slot format combination configured in the UE.

6. The method of claim 5, wherein the UE is configured with a plurality of frequency bands; and is

Wherein each of the at least one slot format combination comprises a plurality of slot formats for the plurality of frequency bands.

7. The method of claim 6, wherein the first and second light sources are selected from the group consisting of,

wherein each of the at least one slot format combination comprises (i) a slot format for a DL frequency band, and (ii) a slot format for a UL frequency band, or

Wherein each of the at least one slot format combinations comprises (i) a slot format for a new radio access technology, NR, frequency band, and (ii) a slot format for a long term evolution, LTE, frequency band.

8. The method of claim 5, wherein the at least one slot format combination configured in the UE is obtained via higher layer signaling, and

wherein the at least one slot format combination is a subset of a plurality of slot format combinations supported in the wireless communication system.

9. The method of claim 1, wherein applying the slot format associated with the reference SCS to a plurality of slots of the first SCS comprises:

converting the slot format to a first slot format associated with the first SCS of the UE.

10. A method of transmitting downlink, DL, control information by a base station, BS, in a wireless communication system, the method comprising:

transmitting first information on a reference subcarrier spacing (SCS) to a User Equipment (UE);

generating DL control information including second information on a slot format related to the reference SCS; and

transmitting the DL control information to a UE group including the UE through a UE group common physical Downlink control channel PDCCH,

wherein, in a state that the reference SCS is different from a first SCS used by the UE, the BS indicates the slot format to the UE based on the reference SCS,

wherein the reference SCS is smaller than the first SCS of the UE, and

wherein a duration of one time slot of the reference SCS is greater than a duration of each of a plurality of time slots of the first SCS of the UE.

11. The method as set forth in claim 10, wherein,

wherein the slot format indicates: whether the symbol corresponds to a downlink D, an uplink U, or a flexible X for each of a plurality of symbols included in a slot corresponding to the slot format; and is

Wherein the second information on the slot format indicates at least one slot format combination configured in the UE.

12. A user equipment, UE, configured to receive downlink, DL, control information in a wireless communication system, the UE comprising:

a receiver;

at least one processor; and

at least one computer memory operatively connected to the at least one processor and storing instructions that when executed cause the at least one processor to perform operations comprising:

receiving, via the receiver, first information regarding a reference subcarrier spacing (SCS);

receiving, via the receiver, DL control information over a UE group common physical Downlink control channel, PDCCH;

obtaining second information on a slot format related to the reference SCS from the DL control information; and

applying the time slot format to a plurality of time slots of a first SCS used by the UE that is different from the reference SCS, wherein the plurality of time slots of the first SCS correspond to time slots of the reference SCS,

wherein the reference SCS is smaller than the first SCS of the UE, and

wherein a duration of one time slot of the reference SCS is greater than a duration of each of the plurality of time slots of the first SCS of the UE.

13. A base station, BS, configured to transmit downlink, DL, control information in a wireless communication system, the BS comprising:

a transmitter;

at least one processor; and

at least one computer memory operatively connected to the at least one processor and storing instructions that, when executed, cause the at least one processor to perform operations comprising:

transmitting first information on a reference subcarrier spacing, SCS, to a user Equipment, UE, via the transmitter;

generating DL control information including second information on a slot format related to the reference SCS; and

transmitting the DL control information to a UE group including the UE via the transmitter and through a UE group common Physical Downlink Control Channel (PDCCH),

wherein in a state that the reference SCS is different from a first SCS used by the UE, the at least one processor indicates the slot format to the UE based on the reference SCS,

wherein the reference SCS is smaller than the first SCS of the UE, and

wherein a duration of one time slot of the reference SCS is greater than a duration of each of a plurality of time slots of the first SCS of the UE.

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